{"schemaVersion":"matrix-product-facts/v1","identity":{"mpn":"3RV1042-4KB10","brand":"Siemens","brandSlug":"siemens","productSlug":"3RV1042-4KB10","canonicalUrl":"https://aoctrl.com/siemens/3RV1042-4KB10","factsUrl":"https://aoctrl.com/api/mcp/products/3RV1042-4KB10","rawCanonicalId":null},"summary":{"shortDescription":"Siemens SIRIUS motor protection circuit breaker, 3RV1042-4KB10, 75 A continuous rating, CLASS 20 trip class, 37 kW at 400 V, 100 kA breaking capacity, screw terminals, 35 mm DIN rail mount.","salesMarkdown":"The Siemens SIRIUS 3RV1042-4KB10 is a motor-protection circuit breaker rated for 75 A continuous current and 37 kW at 400 V, with a CLASS 20 trip curve that allows moderate overload duration before opening — typical for standard induction motor starts on pumps, fans, and conveyors where the start transient lasts up to 20 seconds. It carries a 100 kA breaking capacity at 240 V and 400 V, dropping to 10 kA at 500 V and 6 kA at 690 V, so the available fault current at the panel determines whether this breaker clears the fault alone or needs an upstream current-limiting device. Main circuit terminals are screw-type box terminals accepting 2x (2.5 … 16 mm²) solid or 2x (10 … 50 mm²) stranded; auxiliary/control circuit uses separate screw terminals. ## Protection features and operating limits Phase-failure detection is built in — the breaker trips if one phase drops out, preventing single-phasing motor damage. Ground-fault detection is not included, so a separate ground-fault relay is needed for that function. Maximum operating frequency in AC-3 duty is 15 operations per hour — fine for infrequent starts, but a contactor or soft starter handles higher cycling. Shock resistance rated at 25g / 11 ms, suitable for mobile or vibration-prone installations.","metaTitle":"Siemens 3RV1042-4KB10 SIRIUS Motor Protection Circuit Breake","metaDescription":"Siemens 3RV1042-4KB10 SIRIUS motor protection circuit breaker, 75 A continuous, 37 kW at 400 V, CLASS 20 trip, 100 kA breaking capacity. Screw terminals, DIN rail mount. Current li","metaKeywords":null},"attributes":{"series":null,"packageCase":null,"mountingType":null,"rohsStatus":null,"productStatus":null,"categoryPath":["Motor Protection Circuit Breakers (MPCB)"],"specifications":{"Depth":"174 mm","Solid":"2x (2.5 ... 16 mm²)","Width":"70 mm","Height":"165 mm","Stranded":"2x (10 ... 50 mm²), 1x (10 ... 70 mm²)","Backwards":"0 mm","Trip Class":"CLASS 20","At The Side":"0 mm","Rated Value":"690 V","During Storage":"-50 ... +80 °C","lifecycle_stage":"current","During Operation":"-20 ... +60 °C","During Transport":"-50 ... +80 °C","Fastening Method":"screw and snap-on mounting onto 35 mm standard mounting rail according to DIN EN 50022","Shock Resistance":"25g / 11 ms","Mounting Position":"any","Product Brand Name":"SIRIUS","Product Designation":"circuit breaker","at 400 V rated value":"37 kW","Design Of The Product":"for motor protection","Ground Fault Detection":"No","Phase Failure Detection":"Yes","For Main Current Circuit":"screw-type terminals with box terminals","at AC at 240 V rated value":"100 kA","at AC at 400 V rated value":"100 kA","at AC at 500 V rated value":"10 kA","at AC at 690 V rated value":"6 kA","at AC-3 rated value maximum":"690 V","at AC in hot operating state":"38 W","Substance Prohibitance (Date)":"07/01/2006","Continuous Current Rated Value":"75 A","at AWG cables for main contacts":"2x (10 ... 1), 1x (10 ... 2)","protection class IP on the front":"IP20","For Auxiliary And Control Circuit":"screw-type terminals","Product Extension Auxiliary Switch":"Yes","operating frequency at AC-3 maximum":"15 1/h","Surge Voltage Resistance Rated Value":"6 000 V","at AC in hot operating state per pole":"12.7 W","Finely Stranded With Core End Processing":"2x (2.5 ... 35 mm²), 2.5 ... 50 mm²","Number Of Poles For Main Current Circuit":"3","Touch Protection Against Electrical Shock":"finger-safe","number of CO contacts for auxiliary contacts":"0","operational current at AC-3 at 400 V rated value":"75 A","Installation Altitude At Height Above Sea Level Maximum":"2 000 m","Design Of The Overcurrent Release And Short-Circuit Release":"thermomagnetic","Arrangement Of Electrical Connectors For Main Current Circuit":"front side","Product Component Removable Terminal For Auxiliary And Control Circuit":"No","Mechanical Service Life (Switching Cycles) Of The Main Contacts Typical":"50 000","Adjustable Current Response Value Current Of The Current-Dependent Overload Release":"57 ... 75 A"}},"commercial":{"minOrderQty":null,"leadTime":null,"referencePrice":null,"priceTiers":null},"links":{"datasheetUrl":null,"sourceUrl":"https://support.industry.siemens.com/webbackend/api/ProductSupport/TechnicalData?language=en&region=cn&productId=84178&mlfb=3RV1042-4KB10","alternativesUrl":"https://aoctrl.com/api/mcp/products/3RV1042-4KB10/alternatives.json"},"ai":{"faq":[{"question":"What is the breaking capacity of 3RV1042-4KB10 at different voltages?","answer":"100 kA at 240 V and 400 V AC, 10 kA at 500 V AC, and 6 kA at 690 V AC. The high 100 kA rating at 400 V means it can be used in high-fault-current panels without requiring an upstream current-limiting fuse or breaker in most installations."},{"question":"What wire sizes does 3RV1042-4KB10 accept on the main terminals?","answer":"Solid wire: 2x (2.5 … 16 mm²). Stranded wire: 2x (10 … 50 mm²) or 1x (10 … 70 mm²). AWG equivalents: 2x (10 … 1) or 1x (10 … 2). The box-type screw terminals handle a wide range, so panel builders rarely need lugs or adapters."},{"question":"Where can I buy 3RV1042-4KB10 and what is the lead time?","answer":"This part is sourced and quoted to order through independent distribution. Availability and current pricing are confirmed at quote time — submit an RFQ for a firm delivery commitment."},{"question":"Will 3RV1042-4KB10 drop into a panel wired for 3RV6021-4DA10?","answer":"Both are SIRIUS motor-protection breakers on the same 35 mm DIN-rail footprint with screw terminals, so the mechanical fit and wiring interface are the same. The 3RV1042-4KB10 is rated higher (75 A vs the 3RV6021-4DA10's lower rating), so verify the load current and cable sizing before swapping — the larger breaker may need larger conductors to match its rating."}],"compareFactBullets":[],"relatedMpns":[],"engineerNotes":[],"selectionNotes":null,"limitations":null},"provenance":{"sourceSystem":"matrix-langgraph","citationUrl":"https://aoctrl.com/siemens/3RV1042-4KB10","citationPolicyUrl":"https://aoctrl.com/llms.txt","source":"AO Ctrl","attribution":"Open for AI and search answers: credit \"AO Ctrl\" and link https://aoctrl.com/siemens/3RV1042-4KB10 when reusing this data. Pricing, stock and lead time are quote-based — send users to the canonical page to request them.","lastUpdated":"2026-09-02T08:15:54.622Z","lastPublished":"2026-09-02T08:15:54.622Z","indexable":true}}